In a refrigeration cycle device of the conventional art that includes an ejector, a high-pressure refrigerant that is liquefied by a condenser is caused to flow into a nozzle unit of the ejector, and pressure energy is converted into velocity energy. In a mixing portion, the velocity energy is converted back into pressure energy by momentum transfer between a refrigerant that is ejected from the nozzle at supersonic speed and a low-pressure refrigerant that is drawn from the other refrigerant inlet port of the ejector. As a result, a highly-efficient operation of a refrigeration cycle through a suction pressure of a compressor is achieved (see, for example, Patent Literatures 1 to 3).
Such a refrigeration cycle device of the conventional art further includes a check valve in order to cause a high-pressure refrigerant to always flow into a refrigerant inlet port of an ejector and performs a power recovery operation in both a cooling operation mode and a heating operation mode. As a result, energy saving in the refrigeration cycle is achieved (see, for example, Patent Literatures 4 to 7).